Leak from valve with rad removed

[pody]

We have had the rad in the bathroom removed for a few weeks by the plumber. Since then we have been removing the old tiles and plastering the walls ready for new tiles.
Yesterday it looked like the valve had leaked as it was wet round the floor next to it and some had leaded downstairs into the kitchen. I put a tub next to the valve and there was about 300mm in there this morning.

The valve has been fine for weeks not leaking and its still set to 0 - off, any ideas why this happened? Heating has been on fine for the past few weeks. Also where can we refill the system as the plumber is not back for another week and heating would be nice.

Thanks

 

[regsmyth]

I think your leak might be from the TRV (thermostatic radiator valve) which may well have a built in frost-stat, so that when the room gets cold (like below 5C), the valve automatically opens.
They are often bought with a "lock off cap" which you use instead of the trv cap when the radiator is off.
A few assumptions I know, but it happened to me too.

 

[rebuke]

The fact you say it's set to 0 implies that one side is a TRV (Thermostatic Radiator Valve). These normally have a frost setting built in, so even when set to 0 they will turn on if it gets very cold, to avoid the radiator / pipework freezing. Given the recent cold temperatures, I would believe it possible that could be the cause...

In theory, the valve would have been supplied with a 'decorators cap'. The normal process for removing a radiator is to remove the TRV head, and use the decorators cap to turn off the radiator (Note, don't do this now the radiator is already removed, otherwise when you remove the head the valve will open fully!)

As for refilling, it depends what type of system you have, if it's an open vented system with an F+E tank in the loft, then it should just refill itself from the ball valve, if it's a sealed system (e.g. a combi boiler), then you'll need to refill it, see the wiki for more info: //www.diynot.com/wiki/plumbing:filling_loop